MicroVault: Reliable Storage Unit for IoT Devices

The Internet of Things (IoT) is being deployed at large scale in a wide range of long-life applications. Examples range from Industry 4.0 to smart lighting systems. These applications have diverse requirements of non-volatile storage. However, the flash memory that is used in today's IoT devices offers limited write endurance and must therefore be carefully managed if applications are to deliver on their promises of multiyear lifetimes. Managing the health of flash memory is difficult for application developers, as it requires in-depth hardware and software knowledge, which often needs to the problem being neglected. While various techniques have been proposed to preserve the health of flash memory, prior work tends to focus on a single hardware platform and data type. Furthermore, prior work does not provide lifetime guarantees. This paper tackles this problem by proposing MicroVault, a simple and unified interface for reliable non-volatile data storage on resource-constrained IoT devices. MicroVault enforces developer-specified lifetime guarantees through a range of lifetime extension techniques, which are adaptively applied based upon the needs of the application. Evaluation shows that MicroVault dramatically extends the lifetime of flash memory while minimising overhead.